West Walker Watershed Management Plan

West Walker River Watershed Plan Management Plan March-2007 West Walker River Watershed Management Plan 1 Context Watershed approach California’s watershed programs and Mono County’s involvement Overview of issues and problems Problems linked to potential causes Water quantity Water quality Vegetation change Potential watershed problems and risks Knowledge and information gaps General principles of this watershed plan Main issues and potential solutions List of issues and solutions Potential problems of the future Recommended policies and programs List of goals, objectives, possible actions, and details Applicable best management practices Opportunities for governmental agencies and citizens groups Public education and outreach Monitoring Summary and conclusions Literature cited CONTEXT Watershed Approach The natural unit for considering most water-related issues and problems is the watershed. A watershed can be simply defined as the land contributing water to a stream or river above some particular point. Natural processes and human activities in a watershed influence the quantity and quality of water that flows to the point of interest. Despite the obvious connections between watersheds and the streams that flow from them, water problems are typically looked at and dealt with in an isolated manner. Many water West Walker River Watershed Management Plan 2 problems have been treated within the narrow confines of political jurisdictions, property boundaries, technical specialties, or small geographic areas. Many water pollution problems, flood hazards, or water supply issues have only been examined within a short portion of the stream or within the stream channel itself. What happens upstream or upslope has been commonly ignored. The so-called watershed approach merely attempts to look at the broad picture of an entire watershed and how processes and activities within that watershed affect the water that arrives at the defining point. The watershed approach is simply a means of considering water problems in a comprehensive manner. A companion watershed assessment describes how the 410 square mile watershed influences the quantity and quality of water that flows into the West Walker River above Topaz reservoir at the California/Nevada border. California Watershed Programs and Mono County’s Involvement Within California, the U.S. Environmental Protection Agency and the state Regional Water Quality Control Boards are the principal agencies charged with minimizing water pollution and maintaining or improving water quality. These entities have been largely successful at reducing water pollution that starts at a known point, such as a sewer outfall from a city or a waste pipe from a factory. As these so-called point sources have been brought under control, the agencies found that pollution from broader areas of land was still degrading water quality. Sediment from dirt roads and bare construction sites, pesticide runoff from farms, nutrients and bacteria from livestock operations, chemicals and oil residues from urban streets are all examples of so-called non-point-source water pollution. The agencies concerned with limiting water pollution have adopted the watershed approach to studying and controlling non-point-source pollution. In 1997, the Governor's office directed state agencies that deal with natural resources (e.g., State Water Resources Control Board and Regional Water Quality Control Boards, Department of Fish and Game, Department of Conservation, and Department of Forestry and Fire Protection) to coordinate activities on a watershed basis. In March 2000, California voters passed Proposition 13, the Costa-Machado Water Act, which included substantial grant funding for local watershed management activities. In early 2001, Mono County in cooperation with the Mono County Collaborative Planning Team responded to a request for proposals from the State Water Resources Control Board by submitting two proposals to develop watershed assessments and plans. Both proposals were successful, and scopes of work were developed and eventually approved in 2004. Work began on these projects in January 2005. A watershed assessment for the West Walker River watershed was completed in 2006. The basic concept of a watershed assessment is to describe any known problems concerning water quantity and quality and attempt to connect those problems with conditions, processes, and activities within the watershed. Such linkages between problems and potential causes can provide the basis for subsequent planning and West Walker River Watershed Management Plan 3 management that attempt to address the identified problems. The watershed plan reported here follows from and was based upon the West Walker River watershed assessment. The watershed plan for the West Walker River watershed suggests a variety of approaches and measures for addressing some of the water-related issues and problems identified in the assessment. The plan merely offers guidance and proposals. It has no authority itself, and all implementation of suggested policies and actions will rely on decisions of local jurisdictions, agencies, non-profit organizations, and private citizens. A primary recommendation is that the Mono County Collaborative Planning Team assumes the role of overseeing implementation and revision of this plan. OVERVIEW OF ISSUES AND PROBLEMS The watershed assessment found that the West Walker River watershed has remarkably good water quality and few water problems of “significance”. Any judgmental statement such as the foregoing must be qualified in some context, and the context chosen here is in comparison to the more developed parts of California and the United States. The hydrologic regime and qualities of water within the West Walker River watershed are certainly not pristine or identical to conditions prior to settlement by EuroAmericans in 1860s. However, conditions are not greatly impaired either. The Clean Water Act of 1972 had a general goal for the nation’s waters to become “fishable and swimmable”. By those criteria, the streams and lakes of the West Walker River watershed are in good shape. Nevertheless, conditions could be better. This plan suggests how to improve some of those conditions. A primary challenge is to maintain the current high quality of waters in the West Walker River watershed. The simple fact that the great majority of the watershed is relatively undisturbed accounts for the good condition of the streams and lakes in the watershed. Wherever the level of disturbance of channels, riparian areas, and uplands increases from natural conditions, water quality and aquatic habitat suffer. Antelope Valley at the lower end of the watershed is the most developed part of the watershed, and consequently, the West Walker River as it passes through the valley has the greatest departures from natural conditions. A century of agricultural use of the valley floor and diversion from the river have greatly altered the vegetation, soils, and hydrology of the valley. Roads within the riparian zone probably are the greatest human impact upstream of the Antelope Valley. The capacity of the watershed to support further changes in land use without significant degradation is unknown, but experience in other areas suggests that all reasonable measures that keep surface runoff, sediment, and pollutants on or near the site of disturbance or at least out of streams minimizes the contribution of that change in land use to degradation of water resources and aquatic habitat. West Walker River Watershed Management Plan 4 Problems linked to potential causes Water quantity Additional water is needed downstream to reduce the salinity of Walker Lake. The current legal cases involving water allocation throughout the Walker Lake basin could possibly result in some constraints on consumptive use within Antelope Valley. Water supplies in Antelope Valley appear to be adequate for the time being, but a groundwater management plan is recommended before demand increases to better understand interactions and tradeoffs between surface river and groundwater (Team Engineering and Management, Inc., 2006). Water quality The West Walker River is on the 303(d) list for sedimentation/siltation. Much of the current sediment load is from natural channel processes as the channel readjusts following the 1997 flood. Reconstruction of U.S. Highway 395 through Walker Canyon undoubtedly contributed to the sediment load. Additional accelerated erosion and sedimentation appears related to road and building construction. Much of the local soil erosion from construction, trails, and OHV use is unlikely to impact streams because it is not transported far from the site of erosion. Nutrients and coliform are assumed to be present in agricultural runoff from well-used pastures in Antelope Valley. Microbial processes in the soil may limit the amount of nitrogen release if the area behaves similarly to Bridgeport Valley and Long Valley; however, quantitative studies have not been performed within Antelope Valley. Microbial contamination of streams is assumed to be caused by careless disposal of human and pet wastes. There is some uncertainty about the long-term effectiveness of household septic systems. There is potential, but no direct evidence, for contamination from excessive use of chemical fertilizers on fields, gardens, lawns, and parks. Nutrients from fertilizers that are not incorporated in plant tissue can be leached from soils and enter local streams. West Walker River Watershed Management Plan

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